As the days get colder garden mums (also known as Chrysanthemums) and asters add beautiful color to a withering garden or in a festive pot with seasonal grasses and ornamental cabbage. Plant mums and asters in locations that receive a half a day or more of sun. Space them about 18 to 24 inches apart depending on the size of the plant and water as needed. Mums and asters are hardy plants that will winter over. Mulching with straw is recommended after several hard frosts and should be removed gradually in the spring.  To encourage a compact, bushier look pinch your mums back in the spring when the new growth is 4 to 6 inches tall and repeat pinching during the summer when new shoots grow 3 to 5 inches tall. Mums brighten any garden during the drearier fall months and are reliable fixtures year after year.